Troubleshooting Samsung 153V LCD power supply is the same as troubleshooting crt type. This monitor came in with no power symptoms. If this is your first time repairing this type of power supply, I recommend that you first remove the switched mode power transformer. Then test each component in the parent section before proceeding to verification of the child section. You have to be good at testing basic electronic components to catch the fault.

You can always browse through my website in case you don’t know how to test basic electronic components. If you don’t know the correct way to check, you may be missing a faulty component and this will prevent you from solving the problem. After carefully checking all the components in the power supply section, I found that the filter capacitor has no reading using the digital capacitance meter (open), the two round type fuse also has an open circuit, a short circuit of the 1N4744 15 volt zener diode, and lastly, the TOP247F power IC burned out! Testing the primary winding of the switching power supply with a Dick Smith flyback tester which shows a green bar indicating a good winding.

What we left here was the secondary diode and the filter capacitor. Checking them with an analog meter and an esr meter, I found that they were all in good condition. Other areas like the main board and inverter board look good too (power failures rarely affect these two circuits). We have now confirmed that only five defective components were found. One by one, the components were replaced (except for one fuse) and just before turning on the power supply, be sure to connect a 100-watt light bulb through the live AC line; see photo on my website. Once this is done, you can proceed to turn on the LCD monitor to see the brightness of the bulb.

If it is very bright, this suggests that there is still a short somewhere in the power section. If it dims or goes completely out, you can now place your red probe on the secondary side to check if there is DC present on your respective line. If there are DC voltages present at the outlet, you can disconnect the power, discharge the filter capacitor (for safety), remove the bulb, and reconnect the new fuse to its original location.

Now you are one hundred percent sure that the LCD power supply will not explode once you turn it on. By the way, the filter capacitor is rated at 105 Celsius and you can’t replace it with the 85 Celsius type, otherwise it may open again after using it for a couple of weeks or months. The ventilation of the LCD monitor is not as good as that of the cathode ray tube monitor, because the power supply is completely covered by a large aluminum plate and it can get hot quite quickly. Bottom line, whether you’re repairing a Samsung 153V LCD power supply or another brand of LCD monitor, the procedure is the same. Who knows, the power problem on this monitor is a common fault and in the future you can address this brand of power supply in the shortest possible time. Measuring electronic components is not that difficult, but getting the original parts like the power IC will take a lot of time.